Filter system



FILTER SYSTEM Filed Jan. 23, 1925 WITNESSES: INVENTOR iQ W fiar/es h ////t//r7/1ar/1 WM M E/ ATTORNEY Patented July 4, 1933 UNITED "STA CHARLES WILLIAIVI HORN, OF WILKINSBURG, PENNSYLVANIA, ASS-IGNOR TO WEST- INGHOUSE ELECTRIC 82; IKANUFAC'IUlQING- COMPANY, A CORPORATION OF PENN- SYLVANIA FILTER SYSTEM Application filed January of current output therefrom.

Another object of my invention is to obtain a more nearly complete removal of the alternating-current component from a rectified current. V j

. Another object of my invention is to construct a multi-filter system operative in con junction with a rectifier device.

In prior operation of filter systems, it has been customary to provide a rectifier device, such as a hot-cathode or'other electron-discharge device or a rotating dynamo-electric machine or other type of rectifier means.

All of these devices, however, produce a current which has a steady direct-current component, and superposed thereon is an alternatin -current component. This component has been called a'commutator ripple, or a residual hum, or a variety of other terms. lVhen such rectified current is intended for use with vacuum-tube devices, especially telephonic or radio devices, the alternating-current component is very objectionable, inasmuch as it produces a troublesome sound in attached signal-receiving apparatus. It has been found that, by the use of filter systems comprising combinations of inductances and capacitances, as disclosed in the applications of Michael I. Pupin, Serial No. 69,566, filed December 81, 1915, (Case No. 10,694) and Serial No. 690,586, filed February 4, 1924,

(Case No. 10,7 91) and assigned to the lVestinghouse Electric and Manufacturing Company, a system is produced wherein a plural ity of filter sections are interposed between a rectifier or other current source and a vacuum-tube device. In the system therein dis closed, a considerable attenuation of the alternating-current component is obtained by means of a plurality of filter sections.

My invention provides an additional filter means combined with a system such as that V disclosed by the above-mentioned Pupin applications, and placed between the rectifier 1925 Serial No. 4,277.

and the alternating-current supply} By this means, I am enabled to obtain an attenuation of alternating-current component in the outin excess of the attenuation produced by an equivalent filter means placed between the rectifier and the load.

Other objects and structural details of my invention will be apparent from the followmg description when read in connection with the accompanying drawing, wherein:

The single figure is a diagrammatic representation of a rectifier and filter assembly of a form of my invention applied to a system comprising an electron-discharge device.

In the drawing, a source of alternating current is provided comprising a transformer 1 connected to a generator 2. The transformer 1 comprises coils 3, 4 and5. A rectifier 6, indicated as a hot cathode device, has its cathode, which is an input terminal, connected to the winding 5 of the transformer 1. The coil 4 of the transformer 1 has one lead thereof also connected by a conductor 7 to the cathode circuit of rectifier 6. The anode of the rectifier 6 is connected by a lead 8 to one terminal of a filter means 9 comprising an inductance 10 and capacitances 11 and 12. The anode connection is an output terminal and is connected through the lead 8 and one side of the filter 9. The second lead of the coil 4 is connected by a conductor 14 to the other side of the filter device 9. If desired, the cathode and the anode connections may be reversed, thereby reversing the direction of current fiow without'departing from the'spirit of my invention. The output terminals of the filter device 9 are connected fier rather than, as has been done in the prior art, in the, output side thereof. In the operation of my device, the presence of the induc tance of the coil 4: and the capacitance of the condenser 17- serves asan additional stabilizing means in conjunction with the filter 9 and thereby aiding in'increasing the attenuation of the alternating-current component in the current flowing through rectifier (3. The filter device. comprising inductance 4 and capacitance 17, is placed at a point of effectiveness whereby it is enabled to produce a much higher attenuation of the alternatingcurrent component than is possible by a similar device placed in the position occupied by filter 9. I am, therefore, enabled to obtain a more eifective utilization of the filter device.

This utilization is particularly advantageou's, inasmuch as the coil l serves both as a filter inductance and 7 as an energy-input means for the rectifier 6 and its attached electrical system. 7

WVhile I have shown only one embodiment of my invention in the accompanying drawing, it is capable of various changes and modifications therefrom without departing from the spirit thereof,v and it is desired, therefore, that only such limitations shall be imposed thereon as are indicated in the prior art or in the appended claims.

I I claim as my invention 1. An electrical. rectifier system comprising a source or". variable energy, a power rectifier connected thereto, a load line connected to the rectifier, a condenser connected across said line adjacent to said rectifier and a condenser connected across said source.

2. An electrical rectifier system comprising a source of variable energy constituted by the secondary winding of a power transformer, a power rectifier connected to said secondary winding, a condenser connected across said secondary winding to therewith constitute a filter for minimizing the alternating component of the current traversing the rectifier, and a filter connected to said rectifier at the output side thereof.

3. A rectifier and filter system comprising, in combination, a source of alternating current, a power rectifier having input and output terminals, said rectifier being connected to said source and avplurality of filter sections associated with said rectifier, one of which comprises a condenser connected across said source on the input side of said rectifier.

i. In a supply means for vacuum tubes, a source of alternating current, a condenser across theterminals thereof, a power rectifier connected to said source and a filter connected to said rectifier, the rectifier and filter being in parallel. to said condenser and a load connected to said filter.

5. A rectifying system comprising, in combination, a source of alternating current, a rectifier having input and output terminals connect-ed thereto, a capacitance connected in shunt to the terminals of said alternatingcurrentsourceto constitute an electrical filter therewith and additional filtering means associated with said rectifier.

6. A rectifier and filter system comprising,

in combination, a source of alternatingcun rent, a power rectifier having input andoutput terminals, said rectifier being connected to said source and a plurality of filter sections associated with said rectifier, one of which comprises condenser means connected acrosssaid source on the input side of said rectifier.

In testimony whereof, I have hereunto subscribed my name this 30th day of December 1924.

CHARLES V. HORN. 

